Some moth larvae feed not on plants but on keratin and/or chitin produced by animals. These substances are polymers and are commonly found in bird nests as feathers and raptor pellets. Many qualitative studies have examined the association of keratin/chitin feeding moths with bird nests. However, few studies have quantified the species composition with respect to type of nest and habitat. Hence, we have studied the degree to which the niches of these moths differ in terms of type of nest and habitat. We set-up open-top nest boxes for the Ural owl Strix uralensis (damp exposed nests from which owl chicks were fledged successfully) and artificial bird nests (mesh bags filled with duck down to imitate dry exposed nests) in a deciduous forest and artificial bird nests in an urban setting in Aichi Prefecture, central Japan, and collected the contents of the nests every two months from June to December 2014. We recorded 592 individuals of five keratin/chitin feeding moth species (Tineidae, Tineinae) from the contents. Using non-metric multidimensional scaling and cluster analysis of the relative abundances of individual species in each type of nest in forest and urban settings, these species were classified into three groups: (1) Monopis longella and M. congestella inhabiting forest, (2) M. flavidorsalis and Niditinea tugurialis mainly in damp exposed nests in forest and (3) N. piercella mainly in dry exposed nests in urban areas. This classification was compared with findings of other studies. As a result, these moths probably have different niches with respect to nest type (damp or dry), keratin/chitin as a source of food (raptor pellets or feathers), and habitat (forest or urban area). Furthermore, we suggest that the evolution of larviparity in M. congestella might be related to its preference for feathers as a source of food for the development of its larvae.
Although the Onga River system is relatively small, it is home to three spined loach species, Cobitis takatsuensis, C . sp. ‘yamato’ complex, and C. striata (the Onga form of the middle race). The aim of the present study is to examine the relationship between the distribution pattern of the species and the physical parameters of the habitat. We mapped the distribution of these three species and measured six environmental factors at 86 points in this river system. Model selection was performed with a generalized linear model (GLM) using the AIC (Akaike’s Information Criterion) to find the best model for the distribution pattern of each species. The dependent variable was the presence/absence of each species, and the independent variables were six environmental factors. The environmental factors that had a positive effect were turbidity for C. takatsuensis, turbidity and river gradient for C. sp. ‘yamato’ complex, and turbidity, river gradient and width of dry riverbed for C. striata. In addition, the coexisting fish species also differ among the three loaches. These results revealed that the three spined loach species select particularly different habitats and can therefore coexist in this small river system.
Helminths often occupy defined niches in the gut of their definitive hosts. In the dioecious acanthocephalans, adult males and females usually have similar gut distributions, but sexual site segregation has been reported in at least some species. We studied the intestinal distribution of the acanthocephalan Echinorhynchus borealis von Linstow, 1901 (syn. of E. cinctulus Porta, 1905) in its definitive host, burbot (Lota lota Linnaeus). Over 80% of female worms were found in the pyloric caeca, whereas the majority of males were in the anterior two-thirds of the intestine. This difference was relatively consistent between individual fish hosts. Worms from different parts of the gut did not differ in length, so site segregation was not obviously related to worm growth or age. We found proportionally more males in the caeca when a larger fraction of the females were found there, suggesting mating opportunities influence gut distribution. However, this result relied on a single parasite infrapopulation and is thus tentative. We discuss how mating strategies and/or sexual differences in life history might explain why males and females occupy different parts of the burbot gut., Arto Tuomainen, E. Tellervo Valtonen, Daniel P. Benesh., and Obsahuje bibliografii
Low detectability of small nocturnal carnivores and biases associated to different census methods hamper the interpretation and reliability of the results of censuses and habitat studies of many cryptic and elusive species, especially because of false-negatives and/or lack of negatives. In order to overcome this problem, methodologies based on the use of presence-only data have been used to predict distribution of species. In this paper, we used presence data of two abundant nocturnal carnivores to test for segregation in their habitat. We compared niche overlap between the common genet and the stone marten at two different spatial scales, home range scale and landscape scale, through logistic regression analyses using presence-only data from Biscay, an area in which both species are common and widespread. We found great niche overlap at both spatial scales, but in spite of it logistic regression analyses found statistically significant differences in the predictor values of some variables. Habitat of genets and stone marten was differentiated by areas with dense vegetation that were of importance for genets, and open areas that were characteristic of stone marten habitat. We suggest that competition between the two species causes the observed segregation.